[英]How to extract data from matplotlib plot
I have a wxPython
program which reads from different datasets, performs various types of simple on-the-fly analysis on the data and plots various combinations of the datasets to matplotlib
canvas.我有一个
wxPython
程序,它从不同的数据集读取数据,对数据执行各种类型的简单即时分析,并将数据集的各种组合绘制到matplotlib
画布上。 I would like to have the opportunity to dump currently plotted data to file for more sophisticated analysis later on.我希望有机会将当前绘制的数据转储到文件中,以便稍后进行更复杂的分析。
The question is: are there any methods in matplotlib
that allow access to the data currently plotted in matplotlib.Figure
?问题是:
matplotlib
中是否有任何方法允许访问当前在matplotlib.Figure
绘制的数据?
Jakub is right about modifying the Python script to write out the data directly from the source from which it was sent into the plot; Jakub 修改 Python 脚本以直接从数据发送到绘图的源中写出数据是正确的; that's the way I'd prefer to do this.
这就是我更喜欢这样做的方式。 But for reference, if you do need to get data out of a plot, I think this should do it
但是作为参考,如果您确实需要从绘图中获取数据,我认为应该这样做
gca().get_lines()[n].get_xydata()
Alternatively you can get the x and y data sets separately:或者,您可以分别获取 x 和 y 数据集:
line = gca().get_lines()[n]
xd = line.get_xdata()
yd = line.get_ydata()
The matplotlib.pyplot.gca
can be used to extract data from matplotlib plots. matplotlib.pyplot.gca
可用于从 matplotlib 图中提取数据。 Here is a simple example:这是一个简单的例子:
import matplotlib.pyplot as plt
plt.plot([1,2,3],[4,5,6])
ax = plt.gca()
line = ax.lines[0]
line.get_xydata()
On running this, you will see 2 outputs - the plot and the data:运行此程序时,您将看到 2 个输出 - 绘图和数据:
array([[1., 4.],
[2., 5.],
[3., 6.]])
You can also get the x data and y data seperately.您还可以分别获取 x 数据和 y 数据。 On running
line.get_xdata()
, you will get:在运行
line.get_xdata()
,您将获得:
array([1, 2, 3])
And on running line.get_ydata()
, you will get:在运行
line.get_ydata()
,您将获得:
array([4, 5, 6])
Note: gca
stands for get current axis注意:
gca
代表获取当前轴
它是 Python,因此您可以直接修改源脚本,以便在绘制数据之前转储数据
I know this is an old question, but I feel there is a solution better than the ones offered here so I decided to write this answer.我知道这是一个老问题,但我觉得有一个比这里提供的解决方案更好的解决方案,所以我决定写下这个答案。
You can use unittest.mock.patch
to temporarily replace the matplotlib.axes.Axes.plot
function:您可以使用
unittest.mock.patch
临时替换matplotlib.axes.Axes.plot
函数:
from unittest.mock import patch
def save_data(self, *args, **kwargs):
# save the data that was passed into the plot function
print(args)
with patch('matplotlib.axes.Axes.plot', new=save_data):
# some code that will eventually plot data
a_function_that_plots()
Once you exit the with
block, Axes.plot
will resume normal behavior.一旦退出
with
块, Axes.plot
将恢复正常行为。
To sum up, for future reference:总结一下,供以后参考:
If plotting with plt.plot()
or plt.stem()
or plt.step()
you can get a list of Line2D objects with:如果使用
plt.plot()
或plt.stem()
或plt.step()
绘图,您可以获得 Line2D 对象的列表:
ax = plt.gca() # to get the axis
ax.get_lines()
For plt.pie()
, plt.bar()
or plt.barh()
you can get a list of wedge or rectangle objects with:对于
plt.pie()
、 plt.bar()
或plt.barh()
您可以获得楔形或矩形对象的列表:
ax = plt.gca() # to get the axis
ax.patches()
Then, depending on the situation you can get the data by running get_xdata()
, get_ydata()
(see Line2D ) for more info.然后,根据情况,您可以通过运行
get_xdata()
、 get_ydata()
(请参阅Line2D )获取数据以获取更多信息。
or ie get_height()
for a bar plot (see Rectangle ) for more info.或即
get_height()
用于条形图(请参阅Rectangle )了解更多信息。
In general for all basic plotting functions, you can find what you are looking for by running ax.get_children()一般来说,对于所有基本绘图功能,您可以通过运行ax.get_children()找到您要查找的内容
that returns a list of the children Artists
(the base class the includes all of the figure's elements).返回子
Artists
的列表(基类包括图形的所有元素)。
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